I am a little confused, are you saying that thicker mashes convert faster than thinner mashes?? I always thought it was the other way round (to a point) ie a mash thickness of 2.5:1 will convert slower than 3:1, mainly due to product inhibition effects being greater in thicker mashes.

A reason to mash thinner is to overcome the issue of uneven mash temperature. At 2.5:1 it is much harder to stir the mash than it is at 3:1.

I performed another mash yesterday before I had a chance to read your reply. I reduced my roller mill gap to 0.75mm and mashed at 3.2:1 thickness, I got conversion in about 25-30min @ 68-69C, so its close. Previously it took more like 40-45min, but I was milling more coarsely (0.9mm gap).

Had no problems runoff, but that was mainly due to conditioning the malt with a little water (15-20mL per kg) prior to milling. If I don't do this and mill at such a fine setting the husks are shredded too much.

There will be no flavor transference by using this starter, it is too small a volume and since it did not undergo fermentation and never received excessive oxygen (if you did it right) the oxidative effects upon the alcohols should not have occured.

Eric
I read your information and it really peaked my interest. I had just finished brewing a Bavarian Weizen and was about to brew a second 5 gal.batch After reading your information I said to my self, why not, I was in a perfect position to make a comparison between a 90 minute single infusion and a 20 minute infusion using the same recipe. Be advised that the iodine test showed sugar conversion at the end of 20 minutes.
Thanks
Tom

Assuming i've got well above the cellcount needed from a yeastcake, can I just go ahead and pitch unaerated wort on top? Or would you advise scooping up the yeast, making a starter with it, aerating it and then re-pitching?
Once you've got enough cells, that is, will the yeast need oxygen before it starts fermenting again after a rest, or is aeration solely to help the yeast reproduce?
Sorry if these are silly questions.
Corin

My understanding, Corin, is the oxygen is needed only during the reproduction phase. Additionally, yeast will only reproduce until they reach a certain concentration per volume of wort--how they know when to stop budding I don't know. Therefore, aeration would be unnecessary if you have plenty of yeast as you're saying. Be prepared for an explosive ferment.

thanks for that Bill,
I'll go ahead and pitch my air-free bock wort on the cake tomorrow.
so to put it another way, all the problems people associate with not aerating enough are in fact just problems associated with underpitching?
Corin

Hopefully it is a yeastcake from a secondary, and not the primary. Many will advise against repitching, but if your sanitation was good and you had good results from the present yeast, give the secondary yeast a try. Don't mess with the primary yeast, there is too much trub and potential for off flavors and infections are more prevalent with the primary.

Regarding Eric's post on 4/20 concerning brewing techniques, I checked conversion at 20 minutes and the iodine test was good, however I mashed another 20 minutes and got an additional seven gravity points. Had I not done that I woun'd have hit my efficiency target.
Does that mean I'll need to adjust my recipes to keep the same efficieny for a shorter sparge ?

"I checked conversion at 20 minutes and the iodine test was good, however I mashed another 20 minutes and got an additional seven gravity points."

Clarification needed here: Do you mean that the first wort gravity after recirculation was 7 points lower than after an additional 20 minutes rest and recirculation? And... what measurement are you using... potential points per pound in SG or Plato? What efficiency do you regularly achieve?

"Does that mean I'll need to adjust my recipes to keep the same efficieny for a shorter sparge ?"

This technique does not change sparge duration... you should always sparge for 45~60 minutes @ 168 F, stopping the lauter when the gravity is 2.5 plato.

Post back with more specifics so that I may assess what might have occured.

The research I was exposed to was presented by Charlie Bamforth & Michael Lewis of UC Davis (mash & yeast topics) and a roundtable group of German Brewmasters & Dan Gordon from Gordon Biersch (first wort hopping) both of which were hosted at the Association of Brewer's 2004 Craftbrewing Conference in San Diego.

To read most of the info (some was concluded after the books), get Charlie Bamforth's book "Standards of Brewing: A Practical Approach to Consistency and Excellence " and Michael Lewis'/Tom Young's book "BREWING Second Edition". Both may be acquired at:

The German Brewmaster's roundtable was just that.... we asked random questions of interest, they answered.

Both of the sessions are available on CD from Treefarm Productions.

1. Blowing the Froth Off Some Brewing Fiction: Giving the True Story to the Next Breed of Brewers, Part I:

Speaker(s):
Professor Michael J. Lewis
Charles Bamforth, PhD

Charlie Bamforth takes time off from his central midfield responsibilities at Man. U. to shatter some of the inaccurate paradigms of the brewing world. Michael Lewis will share the stage during the Q & A.

2. Blowing the Froth Off Some Brewing Fiction: Giving the True Story to the Next Breed of Brewers, Part II

Speaker(s):
Professor Michael J. Lewis
Charles Bamforth, PhD

Annually our highest-rated presenter in conference surveys, Michael Lewis is well known for his ability to raise concepts that send brewers back to question established brewing concepts and investigate further in their own brewhouses. Charlie Bamforth will share the stage during the Q & A.

#1. I have always added my first hopping after I have gotten the hot break to be skimmed off by me then added my first hop addition after a vigorous boil and that starts my 60 minute boil time schedule (and reduces the chance of a boilover).

#2. I have found that even with fully modified malts, a feable attempt at a protein rest will result in clearer beer but clear beer is not my main objective, but nice.

#3. I've always suspected that the cooled wort needed a bit of aeration but that the yeast was needing oxygen more so & when doing a starter I always splash the starter to aerate.

When I first read your profound info, I was thinking "Oh No! Next he's going to tell us the lead pipe rumor was just that"!

To sum it up...thanks for the info. I'm not a pro just a Passionate Hobbiest Homebrewer (PHH). Your pro help is awesome!